Process and apparatus for producing carbon blacks

ABSTRACT

The present invention provides processes for introducing a fluid stream into a carbon black reactor and for producing carbon black. According to the present invention, a fluid stream comprising an oxidant, nitrogen, hydrogen, a hydrocarbonaceous material or mixtures thereof is introduced into the effluent flowing through a carbon black reactor in an axial direction.

FIELD OF INVENTION

The present invention relates to new processes and apparatus forproducing carbon blacks.

BACKGROUND

Carbon blacks may be utilized as pigments, fillers, reinforcing agents,and for a variety of other applications, and are widely utilized asfillers and reinforcing pigments in the compounding and preparation ofrubber compositions and plastic compositions. Carbon blacks aregenerally characterized on the basis of their properties including, butnot limited to, their surface areas, surface chemistry, aggregate sizes,and particle sizes. The properties of carbon blacks are analyticallydetermined by tests known to the art, including iodine adsorptionsurface area (I₂ No), nitrogen adsorption surface area (N₂ SA), dibutylphthalate adsorption (DBP), dibutyl phthalate adsorption of crushedcarbon black (CDBP), cetyl-trimethyl ammonium bromide absorption value(CTAB) and Tint value (TINT).

Carbon blacks may be produced in a furnace-type reactor by pyrolyzing ahydrocarbon feedstock with hot combustion gases to produce combustionproducts containing particulate carbon black. A variety of methods forproducing carbon blacks are generally utilized.

In one type of carbon black reactor, such as shown in U.S. Pat. No.3,401,020 to Kester et al., or U.S. Pat. No. 2,785,964 to Pollock,hereinafter “Kester” and “Pollock” respectively, a fuel, preferablyhydrocarbonaceous, and an oxidant, preferably air, are injected into afirst zone and react to form hot combustion gases. A hydrocarbonfeedstock in either gaseous, vapor or liquid form is also injected intothe first zone whereupon pyrolysis of the hydrocarbon feedstockcommences with consequent formation of carbon black. In this instance,pyrolysis refers to the thermal decomposition of a hydrocarbon. Theresulting combustion gas mixture, in which pyrolysis is occurring, thenpasses into a reaction zone where completion of the carbon black formingreactions occurs.

Another type of process equipment utilized to produce carbon blacks isreferred to as a modular or staged reactor. Modular (staged) furnacecarbon black reactors are generally described in U.S. Pat. Reissue No.28,974 and U.S. Pat. No. 3,922,355, the disclosures of which are herebyincorporated by reference.

In certain carbon black production processes a portion of the overalloxidant introduced in the process is introduced downstream of the pointof feedstock injection. U.S. Pat. No. 4,105,750 discloses a process forproducing carbon blacks with lower structure, as reflected by lowerdibutyl phthalate (DBP) absorption numbers, for a given particle size.In the disclosed process a portion of the oxidant introduced in theprocess is injected at a location downstream of the point of feedstockinjection.

WO 93/18094 discloses a process for producing carbon blackscharacterized as adding a secondary oxidant stream to the reactor suchthat the secondary oxidant stream does not interfere with the formationof carbon black particles and aggregates in the reactor. In thedisclosed examples the DBP absorption numbers of the carbon blackproduced utilizing the secondary oxidant stream were lower than the DBPabsorption numbers of the carbon black produced utilizing the samereaction conditions in the absence of the secondary oxidant stream.

Other patents such as U.S. Pat. Nos. 3,607,058; 3,761,577; and 3,887,690also describe the processes for producing carbon black.

The temperatures in a carbon black reactor can range between 2400° F.(1315° C.) and 3000° F. (1648° C.) or greater. The injection ofadditional oxidant, and/or secondary air into the reaction stream, forexample, in the manner described in the aforementioned patents, willgenerally raise the temperature of the reaction stream, and may raisethe temperature of the reaction stream in the region local to the pointof air injection to well above 3000° F. (1648° C.). This temperatureextreme may cause damage to the refractory lining of the reactor and/orshorten the useful life of the refractory lining of the reactor,particularly near the area of additional oxidant injection.

Accordingly, it would be advantageous to have a method and apparatus foradding additional oxidant and/or hydrocarbon containing fluid streamsinto the effluent which minimized refractory problems in the reactor.

It would also be advantageous to have a method and apparatus forproducing-carbon blacks wherein the introduction of additional oxidantand/or hydrocarbon containing fluid streams into the effluent increasedthe structure of the carbon blacks produced by the process, as evidencedby the carbon blacks having an increased DBP absorption value for agiven surface area.

The process and apparatus of the present invention achieve theaforementioned advantages in addition to other advantages that willbecome apparent to those of ordinary skill in the art from the followingdescription.

Although general types of furnace carbon black reactors and processeshave been described, it should be understood that the present inventioncan be used in any other furnace carbon black reactor or process inwhich carbon black is produced by pyrolysis and/or incomplete combustionof hydrocarbons.

SUMMARY OF THE INVENTION

The present invention provides processes and apparatus particularly wellsuited for use in the production of carbon blacks.

An aspect of the present invention are processes and apparatus forsheathing a gaseous stream. A process for sheathing a gaseous stream maycomprise introducing a fluid stream around the outer periphery of thegaseous stream. An apparatus for sheathing a gaseous stream may comprisea hollow vessel, an inlet for introducing the fluid stream into theinterior of the vessel and an outlet to allow the fluid stream to exitthe vessel. The outlet may comprise an annulus, or a plurality of jets.Preferably the vessel is annular, i.e. in the shape of a ring, althoughother shapes are possible. The annulus or outlet jets may be disposedaround the circumference of the vessel.

In a further aspect, the present invention provides a process forproducing carbon blacks that includes sheathing the gaseous streamflowing through the reactor with a fluid stream. The gaseous stream in areactor may comprise a combustion gas stream and/or an effluent stream,formed by introduction of a carbon black yielding feedstock into thecombustion gas stream. The sheathing preferably occurs afterintroduction of feedstock into the combustion gas stream. The fluidstream preferably surrounds the outer perimeter of a combustion gasstream and/or effluent disposing the fluid stream between the combustiongas stream and/or effluent and a reactor wall.

In a further aspect, the present invention provides processes forproducing carbon black. According to the present invention a process forproducing carbon black includes introducing a fluid stream in an axialdirection into a reactor after the point of feedstock injection. Thefluid stream may be introduced in the manner described above.

In another aspect the present invention provides a process for producingcarbon blacks wherein a fluid stream is introduced into a carbon blackreactor after the point of feedstock injection, the process comprising:introducing the fluid stream in an axial direction.

In a process of the present invention the fluid stream may be addedthrough an annulus or a plurality of jets in the axial direction. Theannulus is concentric to introduce the fluid stream around a peripheryof a process stream. The plurality of jets may be disposed in a ring orin multiple rings. The axial direction refers to a direction parallel tothe direction of flow of combustion gases through the reactor. For acylindrical reactor the axial direction is generally parallel to theaxis of the cylinder. As used in the process sense, a “jet” refers to astrong well-defined stream of fluid issuing from an orifice or nozzle.

These aspects of the present invention, and the features discussed belowprovide a means for sheathing the combustion gas stream and carbon blackfeedstock mixture (effluent) exiting the second stage of a modularcarbon black reactor. In a preferred embodiment of the present inventionit is generally preferred that the annulus or jets by which the fluidstream is introduced into the reactor are disposed so as to surround theeffluent stream. As will be appreciated from the appended figures, theeffluent stream may be surrounded through the introduction of the fluidstream around the periphery of the gas stream exiting the second stageof the reactor. The fluid stream introduced into the reactor may beutilized to at least partially divert the effluent gas stream exitingthe second stage away from the walls of the reactor. In this manner,heat damage to the refractory lining of the reactor stage may beminimized.

In particular, an effect of the fluid stream is to counteract thetangentially outward spread of the effluent stream towards the walls ofthe reactor as the effluent progresses down the reactor. Accordingly, afunction of the fluid stream introduced into the reactor is to containor sheath or redirect the effluent stream so that the temperatures towhich the reactor walls are exposed is reduced. Further, introduction ofthe fluid stream in the manner contemplated by the present inventionproduces a more uniform mixing than other methods, thereby minimizinghigh local temperatures.

In a further aspect, the present invention provides an apparatus forintroducing a fluid stream into a carbon black reactor. An apparatus ofthe present invention for introducing a fluid stream into a carbon blackreactor comprises a hollow vessel, an inlet for introducing the fluidstream into the interior of the vessel and an outlet for the fluidstream to exit the vessel. Suitable outlets include an annulus, a jet, aplurality of jets, or mixtures thereof. Preferably, an annulus or aplurality of jets are utilized as an outlet to allow fluid stream toexit the vessel into the reactor. The vessel may be generally annular(in the shape of a ring) or another shapes. The annulus may be disposedconcentrically to the inner and outer diameters of the ring, and/or theoutlet jets may be disposed around the circumference of the ring. Inanother possible embodiment the outlet jets may be disposed inconcentric circles from an inner portion to the outer periphery of thevessel. The inlet for the fluid stream may be disposed radially orsubstantially parallel to the outlet (annulus or jets) to produce anexiting fluid stream without significant swirls. Alternatively, theinlet for the fluid stream may be disposed tangentially, orsubstantially tangentially, to the outlet (annulus or jets) such thatthe exiting fluid stream includes a tangential velocity componentsufficient to create fluid swirls.

The processes of the present invention may be practiced with anapparatus of the present invention, or with other apparatus known in theart or derivable by those of ordinary skill in the art based on thedisclosure of the present invention.

In a further aspect the present invention includes an apparatus forproducing carbon blacks comprising the apparatus of the presentinvention for introducing a fluid stream. A preferred apparatus is amodular reactor comprising: a first, or combustion, stage where anoxidant is contacted with a fuel to produce a stream of combustion gasesat a temperature sufficient to pyrolyze a carbon black yieldingfeedstock; a second, or feedstock introduction, stage where a carbonblack yielding feedstock is introduced into the combustion gases; and athird, or reaction, stage wherein the mixture of combustion gases andfeedstock react to produce carbon black, the reactor further comprisingan apparatus for introducing a fluid stream into the second or thirdstage of the reactor after the point of feedstock injection.

An advantage of the present invention is that the method of introductionof the fluid stream will minimize refractory lining wear generallyassociated with the introduction of secondary fluid streams into areactor.

A further advantage of the present invention is that the process forproducing carbon blacks of the present invention may be utilized toproduce carbon blacks having increased structure, as reflected byincreased DBP absorption values, for a given surface area.

Other advantages of the present invention will become apparent from thefollowing more detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a cross-sectional view of a portion of a modular furnacecarbon black reactor according to an embodiment of the presentinvention.

FIGS. 2 a and 2 b depict embodiments of apparatus of the presentinvention for introducing a fluid stream into a carbon black reactor.

FIG. 3 is a cross-sectional view of a portion of the modular furnacecarbon black reactor which was utilized in the Examples described below.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides processes for sheathing a gas stream in areactor the processes comprising introducing a fluid stream around theouter periphery of the gas stream. In a carbon black production process,the fluid stream is introduced around the outer periphery of thecombustion gas stream and/or effluent stream. The fluid stream ispreferably introduced in an axial direction, the axial directionreferring to a direction substantially parallel to the overall directionof flow of the gas stream. The fluid stream may be introduced in aco-current direction to the direction of flow of the gas stream orintroduced in a counter-current direction. Preferably the fluid streamis introduced in a co-current direction.

The present invention also provides processes for producing carbon blackcomprising introducing a fluid stream into a gaseous process stream tosheath the gaseous process stream. In a typical carbon black reactor,the introduction may occur downstream of the point of feedstockinjection. An embodiment is process for producing carbon blackcomprising: introducing a fluid stream to sheath a process stream afterintroduction of a feedstock into the process stream.

The process may further comprise: introducing the fluid stream in anaxial direction, the axial direction referring to a directionsubstantially parallel to the overall direction of flow of a combustiongas stream/effluent in the reactor. The fluid may be introduced with orwithout swirls and co-currently or counter-currently.

In a process of the present invention, the introduced fluid stream ispreferably a gaseous stream comprising at least one of the followingcomponents: an oxidant, nitrogen, hydrogen, a hydrocarbonaceous materialor mixtures thereof An “oxidant” as used herein refers to a compositioncomprising oxygen, such as atmospheric air, oxygen-enriched air,combustion products of hydrocarbon fuels and air and/or oxygen, ormixtures of these streams. A “hydrocarbonaceous material as used hereinrefers to a composition comprising a hydrocarbon such as a hydrocarbonfuel, a gas stream including an incompletely combusted hydrocarbon fuel,such as the combustion gas stream from the carbon black productionprocess, or mixtures of these streams.

The present invention also provides an apparatus for practicing theprocess of the present invention and introducing a fluid stream in anaxial manner. An apparatus of the present invention comprises: a hollowvessel, preferably a hollow ring, an inlet or inlets for introducing afluid stream into the interior of the vessel and at least one outlet toallow the fluid stream to exit from the vessel. The outlet may comprisean annulus, or a plurality of annuli. The outlet may also comprise a jetor a plurality of jets.

The inlet may be disposed radially or in an axial directionsubstantially parallel to the axial direction of the outlet to producean outlet stream without significant swirls. Alternatively the inlet maybe disposed in a direction tangential to the axial direction of theoutlet to produce an outlet stream with swirls. Further details relatingto the process and apparatus for introducing a fluid stream into acarbon black reactor are set forth below with reference to the processesand apparatus of the present invention for producing carbon blacks.

According to an embodiment of a process of the present invention, afluid stream comprising an oxidant, nitrogen, hydrogen, ahydrocarbonaceous material, or mixtures thereof is introduced into theeffluent flowing through a carbon black reactor in an axial direction.In one embodiment the fluid stream comprises atmospheric air, with orwithout, oxygen enrichment. In another embodiment, the fluid streamcomprises an industrial gas stream comprising hydrocarbons, hydrogen,carbon monoxide, carbon dioxide and/or steam. An example of anindustrial gas stream is tail gas from a carbon black productionprocess.

In one aspect, a process of the present invention for producing carbonblack comprises:

-   -   a) reacting an oxidant, primary fuel, and carbon black feedstock        in a reactor to form an effluent composed of carbon black and        combustion gases;    -   b) injecting a fluid stream into effluent in a direction axial        to the direction of the flow of the effluent through the        reactor;    -   c) passing the resulting effluent through the reactor; and    -   d) cooling, separating, and recovering the carbon black product,        the fluid stream comprising an oxidant, nitrogen, hydrogen, a        hydrocarbonaceous material, or mixtures thereof. The        introduction of the fluid stream preferably results in the        production of carbon blacks having increased structure, as        reflected by an increased DBP absorption value, for a given        iodine number (I₂No.) surface area in comparison to carbon        blacks produced utilizing similar process conditions in the        absence of the fluid stream introduction.

A process of the present invention may be advantageously performed in amodular type carbon black reactor including at least three stages. Withreference to this type of reactor, an embodiment of process of thepresent invention for producing carbon blacks comprises:

-   -   generating a stream of combustion gases in a first stage of a        reactor having a velocity sufficient to flow through subsequent        stages of the reactor and a temperature sufficient to pyrolyze a        carbon black yielding feedstock;    -   injecting a carbon black yielding feedstock into the combustion        gas in a second stage of the reactor to produce an effluent        composed of carbon black and combustion gases;    -   introducing a fluid stream in a direction axial to the flow of        the effluent after the injection of carbon black yielding        feedstock, the resulting effluent passing through the third        stage of the reactor; and    -   cooling, separating, and recovering the carbon black product.        Preferably the fluid stream is introduced in the third stage of        the reactor, however as will be recognized by those of ordinary        skill in the art the fluid stream may be introduced at any point        subsequent to the introduction of feedstock.

The fluid stream may comprise an oxidant, nitrogen, hydrogen, ahydrocarbonaceous material, or mixtures thereof. The introduction of thefluid stream preferably results in the production of carbon blackshaving increased structure, as reflected by an increased DBP absorptionvalue, for a given iodine number (I₂No.) surface area in comparison tocarbon blacks produced utilizing similar process conditions in theabsence of the fluid stream introduction.

In a “staged” or “modular” reactor, a liquid or gaseous fuel is reactedwith an oxidant, preferably air, in a first stage to form hot combustiongases. This stage has been referred to the “burner” stage, thecombustion stage and/or the combustion zone of the reactor.

The hot combustion gases pass from the first stage, downstream into anadditional reactor stage or stages. Generally the additional reactorstage(s) includes at least a feedstock injection stage and a reactionstage. The feedstock injection stage may be located between the first(or combustion) stage and the reaction stage and comprise a choke, orzone of restricted diameter, which is smaller in cross section than thecombustion stage or the reaction stage. The zone of restricted diameteris also known as the transition zone to those of ordinary skill in theart.

In the production of carbon blacks a hydrocarbonaceous feedstock isinjected at one or more points into the path of the hot combustion gasstream in the feedstock injection stage. The feedstock may be injectedinto the path of the hot combustion gases upstream of, downstream of,and/or in the restricted diameter zone. The hydrocarbonaceous feedstockmay be liquid, gas or vapor, and may be the same as or different fromthe fuel utilized to form the combustion gas stream. Generally thehydrocarbonaceous feedstock is a hydrocarbon oil or natural gas.However, other hydrocarbonaceous feedstocks such as acetylene are knownin the art.

Following the point of feedstock introduction, the feedstock is mixed,atomized and vaporized into the combustion gas stream. The mixture ofcombustion gases and vaporized feedstock then enters a stage of thereactor referred to herein as the reaction stage. Although pyrolysisbegins upon injection of the feedstock into the combustion gas stream,the conversion of vaporized hydrocarbon feedstock to carbon blackprimary particles and aggregates continues in the reaction stage. Theresidence time of the feedstock, combustion gases, and carbon blacks inthe reaction zone of the reactor is sufficient, to allow the formationof carbon blacks. The mixture of combustion gases and carbon blacks inthe reaction zone of the reactor is hereinafter referred to, throughoutthe application, as the effluent. After carbon blacks having the desiredproperties are formed, the temperature of the effluent is lowered tostop the major reactions. This lowering of temperature of the effluentto stop the major reactions may be accomplished by any known manner,such as by injecting a quenching fluid, through a quench, into theeffluent. As is generally known to those of ordinary skill in the art,the major reactions are stopped when the desired carbon blacks have beenproduced in the reactor, as is determined by sampling the carbon blackand testing for analytical properties. After the reactions have beenstopped and the effluent sufficiently cooled by any known means, theeffluent generally passes through a bag filter, or other separationsystem to collect the carbon black.

In both types of processes and reactors described above, and in othergenerally known reactors and processes, the hot combustion gases are ata temperature sufficient to effect pyrolysis of the hydrocarbonaceousfeedstock injected into the combustion gas stream. The temperature ofthe combustion gas stream prior to injection of carbon black yieldingfeedstock is generally at least 2400° F. (1315° C.). After injection ofthe carbon black yielding feedstock, the temperature of the processstream will rise and may reach 3000° F. (1648° C.) or higher. In view ofthese temperatures, and the heat generated by the carbon blackproduction process, reactors for producing carbon black may includelinings made from refractory materials capable of withstanding the hightemperatures.

A process of the present invention for producing carbon blacks includesmeans for sheathing the effluent stream as it passes through at least aportion of the reactor. By way of example, with reference to a modularcarbon black reactor, a process of the present invention may comprise:

-   -   generating a stream of combustion gases in a first stage of a        reactor having a velocity sufficient to flow through subsequent        stages of the reactor and a temperature sufficient to pyrolyze a        carbon black yielding feedstock;    -   injecting a carbon black yielding feedstock into the combustion        gas stream in a second stage of the reactor to produce an        effluent composed of carbon black and combustion gases;    -   sheathing the effluent stream as the effluent stream exits the        second stage of the reactor, the sheathed effluent stream        passing through the third stage of the reactor; and    -   cooling, separating, and recovering the carbon black product.        The step of sheathing the effluent stream will preferably divert        the effluent stream from the walls of the third stage of the        reactor, at least at the point of initial sheathing. The means        for sheathing the effluent stream may comprise introducing a        fluid stream in a direction axial to the flow of the effluent to        surround the effluent stream exiting the second stage of the        reactor.

A cross-sectional view of a type of reactor in which the process of thepresent invention may be practiced is depicted in FIG. 1. As will beunderstood, the process of the present invention does not require anymodification of the carbon black reactor, other than the provision of ameans for injecting the oxidant-containing stream, and therefore may bepracticed in other types of carbon black reactors, such as the typesgenerally discussed in the Background section.

One embodiment of a modular apparatus for producing carbon black of thepresent invention comprises:

-   -   a combustion zone having an upstream and a downstream end and at        least one port to allow the introduction of a fuel and an        oxidant;    -   a zone of converging diameter having an upstream and a        downstream end and converging from the upstream end towards the        downstream end, the upstream end being connected to the        downstream end of the combustion zone;    -   a transition zone having an upstream and a downstream end, the        upstream end being connected to the downstream end of the zone        of converging diameter, the transition including at least one        port to allow the introduction of a feedstock;    -   an apparatus for introducing a fluid stream into the reactor in        a direction axial to the flow of a process stream in the        reactor, the apparatus having an upstream and a downstream end,        the upstream end being connected to the downstream end of the        transition zone;    -   a reaction zone having an upstream and a downstream end, the        upstream end being connected to the downstream end of the        transition zone or zones;    -   a quench zone having an upstream and a downstream end, the        upstream end being connected to the downstream end of the        reaction zone, the quench zone including at least one port to        allow the introduction of a quenching fluid; and    -   apparatus for separating and collecting carbon black connected        to the downstream end of the quench zone or zones.        The apparatus for introducing a fluid stream into the reactor in        an axial direction may comprise a hollow vessel; at least one        inlet, preferably a plurality of inlets, for introducing a fluid        stream into the interior of the vessel and an outlet to allow        the fluid stream to exit from the vessel. The outlet may        comprise an annulus, a plurality of annuli, a jet or a plurality        of jets. The inlet(s) of the hollow vessel may be disposed        radially or in an axial direction substantially parallel to the        axial direction of the outlet to produce an outlet fluid stream        without significant swirls. Alternatively, the inlet(s) of the        hollow vessel may be disposed in a direction tangential to the        axial direction of the outlet to produce an outlet fluid stream        with swirls.

FIG. 1 depicts, in cross-sectional view, a modular, also referred to asa “staged”, furnace carbon black reactor of the type generally disclosedin U.S. Pat. No. 3,922,335, the disclosure of which is herebyincorporated by reference. FIG. 1 illustrates a furnace carbon blackreactor 2, having a first-stage 10, which has a zone of convergingdiameter I 1; a second stage 12; and a third reactor stage 18. Feedstock30 is injected at feedstock injection points 32 in the second stage 12of the reactor. Quench 40, is located at point 42 in the third reactorstage 18 to introduce a quench fluid 50 into the reactor.

An apparatus of the present invention for introducing a fluid stream 70is located downstream of the point of feedstock injection at point 72.The apparatus 70 includes inlet ports 71 and an outlet annulus 73 tointroduce a fluid stream in an axial direction into the third reactorstage 18. In the depicted embodiment inlet ports 71 are disposedsubstantially parallel to the outlet annulus 73 to introduce the fluidstream into the reactor without swirls.

FIGS. 2 a and 2 b depict embodiments of an apparatus of the presentinvention for introducing a fluid stream into the reactor. FIG. 2 adepicts an end view of an embodiment of an apparatus, 70 of the presentinvention for introducing a fluid stream into the reactor. The viewshown is the end including an outlet annulus 73. In the embodiment shownin FIG. 2, inlet ports 71 are disposed tangentially to the annulus 73.As a result the annulus will introduce the fluid stream into the reactorwith swirls.

FIG. 2 b depicts an end view of an alternative embodiment of anapparatus, 70 of the present invention for introducing a fluid streaminto the reactor. The view shown is the end including a plurality ofoutlet jets 72. In the embodiment shown in FIG. 2, inlet ports 71 aredisposed tangentially to the outlet jets 72. As a result the outlet jetswill introduce the fluid stream into the reactor with swirls. Inaddition, or alternatively, the outlet apertures for outlet jets 72 maybe configured to impart swirl to the fluid stream.

FIG. 3 depicts an alternative embodiment of a modular carbon blackreactor for practicing a process of the present invention. The reactorconfiguration depicted in FIG. 3 was utilized in the following examples.

Referring to FIG. 3, carbon black reactor 3, has a first-stage 10, whichhas a zone of converging diameter 11 that includes a stepped portion; asecond, feedstock injection stage 12; and a third, reactor stage 18.Feedstock 30 is injected at feedstock injection points 32 in the secondstage 12 of the reactor. Quench 40, is located at point 42 in the thirdreactor stage 18 to introduce a quench fluid 50 into the reactor.

The diameter of the first, combustion stage, 10, up to the point wherethe zone of converging diameter, 11, begins is shown as D-1; thediameter at the step in zone 11 is shown as D-2, and the diameter ofzone 12, as D-3. The length of the first-stage combustion zone, 10, upto the point where the zone of converging diameter, 11, begins is shownas L-1; the length of the zone of converging diameter up to the step isshown as L-2, and from the step to the beginning of the feedstockinjection zone as L-3. The overall length of the feedstock injectionzone is shown as L-4. The distance between the end of zone 11 and thepoint of feedstock injection 32 is shown as F.

The reactor 3, includes an apparatus of the present invention forintroducing a fluid stream 70 located downstream of the point offeedstock injection at point 72. The apparatus 70 includes inlet ports71 and an outlet annulus 73, as depicted in FIG. 2 a, to introduce afluid stream in an axial direction into the third reactor stage 1 8. Inthe depicted embodiment inlet ports 71 are disposed radially to annulus73 to introduce the fluid stream into the reactor without swirls.Dimensions of apparatus 70 are shown as L-5 and L-6.

In the reactor depicted in FIG. 3 the entrance to the third reactorstage 18 includes a zone of expanding diameter 19, followed by a steppedzone 20, a zone of increasing diameter 21 and then a first zone ofuniform diameter 22. After an angled portion of the reactor there is asecond zone of uniform diameter 24.

D-4 represents internal diameter of the annulus 73 utilized in theintroduction of the fluid stream into the reactor. D-5 represents theexternal diameter of the annulus 73. The diameter of zone 19 at itswidest point is shown as D-6 and the length of zone 19 as L-7. Thediameter of zone 21 at its narrowest point is shown as D-7 and thelength of zone 21 as L-8. The diameter of zone 22 is shown as D-8 andthe length of zone 22 as L-9.

The length of zone 23 is shown as L-10. The drop at the top of thereactor between zone 22 and zone 24 is shown as H-1 and the drop at thebottom of the reactor between zone 22 and zone 24 is shown as H-2. Thediameter of zone 24 is shown as D-9.

The distance from the start of the third reactor stage 18 to point 42where the quench is located is shown as Q.

Referring to FIG. 1 or FIG. 3, to produce carbon blacks, hot combustiongases are generated in combustion zone 10 by contacting a liquid orgaseous fuel with a suitable oxidant stream such as air, oxygen,mixtures of air and oxygen or the like. Among the fuels suitable for usein contacting the oxidant stream in combustion zone, 10, to generate thehot combustion gases are included any of the readily combustible gas,vapor or liquid streams such as natural gas, hydrogen, carbon monoxide,methane, acetylene, alcohol's, or kerosene. It is generally preferred,however, to utilize fuels having high content of carbon-containingcomponents and in particular, hydrocarbons. The ratio of air to fuelvaries with type of fuel utilized. When natural gas is utilized toproduce the carbon blacks of the present invention, the ratio of air tofuel may be from about 10:1 to about 100:1. To facilitate the generationof hot combustion gases, the oxidant stream may be preheated.

The hot combustion gas stream flows downstream from zones 10 and 11 intozones 12 and then 18. The direction of the flow of hot combustion gasesis shown by the arrow in FIG. 1 or 3. Carbon black-yielding feedstock,30, is introduced at point 32. The distance from the end of the zone ofconverging diameter, 11, downstream to point 32 is shown as F. In theexamples described herein, carbon black-yielding feedstock, 30, wasinjected through a plurality of jets which penetrate into the interiorregions of the hot combustion gas stream to insure a high rate of mixingand shearing of the hot combustion gases and the carbon black-yieldingfeedstock so as to rapidly and completely decompose and convert thefeedstock to carbon black particles and aggregates.

Suitable for use herein as carbon black-yielding hydrocarbon feedstocks,which are readily volatilizable under the conditions in the reactor, areunsaturated hydrocarbons such as acetylene; olefins such as ethylene,propylene, butylene; aromatics such as benzene, toluene and xylene;certain saturated hydrocarbons; and volatilized hydrocarbons such askerosene's, naphthalene's, terpenes, ethylene tars, aromatic cyclestocks and the like.

The mixture of carbon black-yielding feedstock and hot combustion gasesflows downstream through zone 12 into the carbon black reactor, zone 18.A fluid stream, comprising an oxidant, nitrogen, hydrogen, ahydrocarbonaceous material, or mixtures thereof, is introduced into thereaction stream in an axial direction through apparatus 70 and annulus73 at the entrance of reactor stage 18. The fluid stream is introducedunder sufficient pressure to penetrate the interior region of thereactor stage 18.

Quench 40, located at point 42, injecting quenching fluid 50, isutilized to stop the reactions in the effluent. According to the processof the present invention, quench 40, is located at a position 42 whichallows reactions in the effluent to occur until carbon blacks having thedesired properties are formed. Q is the distance from the beginning ofzone 18 to quench point 42, and will vary according to the position ofthe quench.

After the mixture of hot combustion gases and carbon black yieldingfeedstock is quenched, the cooled gases pass downstream into anyconventional cooling and separating devices whereby the carbon blacksare recovered. The separation of the carbon black from the gas stream isreadily accomplished by conventional means such as a precipitator,cyclone separator or bag filter. This may be, but is not necessarily,followed by some means of densification, such as pelletization anddrying.

The features and advantages of the present invention are furtherillustrated by the following examples.

The following testing procedures are used in the determination andevaluation of the analytical properties of the carbon blacks produced inthe examples. Iodine number (I₂ No.) of the carbon blacks was determinedaccording to ASTM Test Procedure D1510. The DBP (Dibutyl PhthalateAbsorption number) of the carbon black pellets was determined accordingto the procedure set forth in ASTM D3493-86.

EXAMPLES

Experiments were conducted in a carbon black producing process in areactor substantially as described herein, and as depicted in FIG. 3with the geometry set forth below. In all examples, the primary fuel forthe combustion reaction was natural gas supplied to the carbon blackforming process at an ambient temperature of approximately 298 K (77°F.). The liquid feedstocks utilized in all examples were commerciallyavailable hydrocarbon mixtures.

A fluid stream comprising combustion air was introduced without swirl ineach example through apparatus 70 and annulus 73. The reactor geometryand run conditions were as follows: Example 1 2 D-1, cm 19.0 19.0 D-2,cm 14.0 14.0 D-3, cm 10.9 10.9 D-4, cm 15.2 15.2 D-5, cm 18.7 18.7 D-6,cm 33.3 33.3 D-7, cm 76.2 76.2 D-8, cm 91.4 91.4 D-9, cm 68.6 68.6 L-1,cm 61.0 61.0 L-2, cm 30.5 30.5 L-3, cm 14.0 14.0 L-4, cm 27.6 27.6 L-5,cm 1.9 1.9 L-6, cm 5.0 5.0 L-7, cm 7.6 7.6 L-8, cm 7.6 7.6 L-9, cm 621.0621.0 L-10, cm 61.0 61.0 H-1, cm 34.3 34.3 H-2, cm 11.4 11.4 F, cm 2.52.5 Q, m 10.7 10.7 Point 32, Tips # and Size, 6 × 1.32 6 × 1.78 mmFeedstock rate, kgh 677 728 Feedstock Temp. C. 176 179 K+ addition, ppm8 8 Feedstock Total Air, nm³h 1870 1879 Primary Comb. Air, nm³h 18321315 Primary Comb. Air, 402 402 Temp. C. Primary Nat. Gas, nm³h 76 54Primary Nat. Gas Temp. C. 15 15 Air/Gas Burn Ratio 9.85 9.85 FluidInjection nm³h 38 564 Burner Equivalence Ratio 0.40 0.40 TotalEquivalence Ratio 4.00 4.18 % Axial Air 2 30 Carbon Black PropertiesExample 1 Example 2 I2No., m²/g 30.1 30.0 DBP, cc/100 g 68 74.6

Examples 1-2 illustrate the effect of fluid stream addition on thestructure of the carbon blacks produced by the process, as reflected bythe DBP of the carbon blacks. As shown in Example 2, increasing the rateof fluid addition into reactor stage 18 results in a carbon black havingan approximately 10% greater DBP in comparison to Example 1.

It should be clearly understood that the forms of the present inventionherein described are illustrative only and are not intended to limit thescope of the invention. The present invention includes all modificationsfalling within the scope of the foregoing disclosure and the followingclaims.

1-10. (canceled)
 11. A modular apparatus for producing carbon blackcomprising: a combustion zone having an upstream and a downstream endand at least one port to allow the introduction of a fuel and anoxidant; a zone of converging diameter having an upstream and adownstream end and converging from the upstream end towards thedownstream end, the upstream end being connected to the downstream endof the combustion zone; a transition zone having an upstream and adownstream end, the upstream end being connected to the downstream endof the zone of converging diameter, the transition including at leastone port to allow the introduction of a feedstock; an apparatus forintroducing a fluid stream into the reactor in a direction axial to theflow of a process stream in the reactor, the apparatus having anupstream and a downstream end, the upstream end being connected to thedownstream end of the transition zone; a reaction zone having anupstream and a downstream end, the upstream end being connected to thedownstream end of the transition zone or zones; a quench zone having anupstream and a downstream end, the upstream end being connected to thedownstream end of the reaction zone, the quench zone including at leastone port to allow the introduction of a quenching fluid; and apparatusfor separating and collecting carbon black connected to the downstreamend of the quench zone or zones.
 12. The modular apparatus for producingcarbon black of claim 11 wherein the apparatus for introducing a fluidstream into the reactor in an axial direction comprises a hollow vessel;at least one inlet for introducing a fluid stream into the interior ofthe vessel and an outlet to allow the fluid stream to exit from thevessel.
 13. The apparatus of claim 12 wherein the outlet comprises anannulus.
 14. The apparatus of claim 12 wherein the inlet of the hollowvessel is disposed radially to the outlet to produce an outlet fluidstream without significant swirls.